Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem
lean and variable A/F ratio
blarson:
I pulled the base plate apart and did the primary throttle shafts last night. They weren't binding at all like I found before but I did them anyway which is probably for the best because I did find some wear in the shaft once I had it all the way apart. I lubed the shafts up with some 3in1 oil and put it back together. The secondaries were quite lose but I didn't worry about them per suggestion in Cliff's book. If they bind again on a throttle snap I'll just go with a heavier return spring because they are completely free to move. Cliff's self tapping drill bit really made that job a piece of cake.
I double checked the base plate, air horn, and main body while I was doing the shafts to make sure they were straight with my machinists straight edge and they were. It also appeared that the gasket between the base plate and the main body was slightly compressed equally all the way around leading me to believe that area to be fine.
My intent is to go to 15:1 for fuel economy through as much range of the throttle as I can get. I will have to do emissions when I move in a few months so I can't be too far from stoich to pass.
Shark Racer:
Yes, stick with ~13.5 at idle but 15:1 is a good target for off-idle, cruise.
I need to play with my off-idle a bit because it's in the high 13s and that's making me high on CO.
blarson:
I'm still lean with a new pump, raised float, 3.5 turns APT, and bushed throttle shafts so bigger mains it is. A heavier return spring solved the problem with not returning to idle.
Cliff Ruggles:
Did you raise the APT more than 3.5 turns? It may like more fuel at part throttle, nothing wrong with going up to 4 to 4.5 turns or so and seeing if it responds favorably....Cliff
blarson:
Up goes the APT. Is there such a thing as a max APT height?
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